1. Field
The present disclosure relates to a touch sensor, a manufacturing method thereof, and a display device including the same.
2. Description of the Related Art
Electronic devices (such as a liquid crystal display (LCD), an organic light emitting diode (OLED) display, or an electrophoretic display) may include a touch sensing function for enabling interaction with a user. A touch sensing function is used to obtain touch information (such as whether an object approaches or contacts a touch screen) and a touch position by sensing a change in pressure, charges, light, etc., that are applied onto the screen of a display device, when a user writes text or draws a figure by approaching or touching the screen using a finger or a touch pen.
Such touch sensing functions of the various electronic devices can be realized by a touch sensor. The touch sensor can be classified into various types (kinds) such as a resistive type, a capacitive type, an electromagnetic (EM) type, an optical type, etc.
For example, in the resistive type of touch sensor, two electrodes separated and facing each other may come into contact due to pressure from an external object. When the two electrodes contact each other, the touch position and/or the like can be determined by detecting a voltage change due to a change in resistance at a touch position.
The capacitive type of touch sensor includes a sensing capacitor including a plurality of sensing electrodes for transmitting a detection signal, and determines whether a touch occurs or not and a touch position by detecting a change in capacitance of the sensing capacitor or an amount of charge when a conductor such as a finger approaches the touch sensor. The capacitance type of touch sensor may include a plurality of touch electrodes for sensing the touch, which are located in a touch sensing area to sense a touch, and signal-transmitting wiring connected to the touch electrodes. The signal-transmitting wiring may transmit a sensing input signal to the touch electrodes, and/or may transmit a sensing output signal of the touch electrodes generated by the touch to a sensing signal controller.
In general, the signal-transmitting wiring may be located in a peripheral area around a touch sensing area of a touch sensing panel and/or in the touch sensing area.
When a heavy and fragile glass substrate is used in the various electronic devices such as the display devices and the like, there are some limitations in portability and large screen display. Therefore, recently, a flexible display device using a plastic substrate, which is light, strong against impacts, and/or highly flexible, as a substrate has been actively developed. Accordingly, the touch sensor attached to or integrated into the electronic devices should also have flexibility.
Recently, flexible touch sensors that are actively being developed may include, for example, a transformable part that is foldable/bendable, rollable, stretchable in at least one direction, and/or elastic. The flexible touch sensor includes a plurality of touch electrodes, and the touch electrodes may have flexibility to prevent defects after being transformed.
For example, as a material for forming the flexible touch electrodes, various materials such as a metal nanowire such as a silver nanowire (AgNw), carbon nanotubes, graphene, a metal mesh, and/or a conductive polymer have been developed.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.